Bibliographical Notices. 271 



structure and the external form of the minute shells he has had to 

 do with, our author has been led to determine and note the geome- 

 trical relationship and exact measurements of spirals and chambers, 

 and has made angles and proportions of greater importance in the 

 specific characters of the organisms than his predecessors thought 

 of doing. Had there been but few of the spiral (helicostegian) 

 forms, and but few of those with alternating (enallostegian) cham- 

 bers, some definite limits of size, form, and structure would have 

 been far more easily recognized as of permanent occurrence among 

 Foraminifera than are usually found to obtain. The gradations, 

 however, in amount of angularity with the alternating chambers 

 are even more insensible than those in the relative size and the 

 setting-on of chambers, and in the modifications of septal aperture, 

 in any series of Foraminifera. The nature of the dorsal spire, 

 whether simple and either " concho-spiral" or " logarithmic-spiral," 

 or compouud and combining both kinds, is of importance in Von 

 MoUer's differentiations ; and so also are the characters of the form 

 and shell-structure. In this last feature, however, the discrepancies 

 between his observations and those of H. B. Brady on apparently 

 similar shells are so very great that, unless shell-structure varied 

 with regional conditions, doubt must exist as to whether the author 

 and his artists have quite mastered the intimate structure of the 

 shells in every detail ; for they have as much omitted the sandiness 

 usually present in Endothyra &c. as Messrs. Brady and HoUick's 

 drawings omit the large pores so numerous and regular in the 

 Russian figures. H, B. Brady intimates (Monograph, Pal. Soc, 

 p. 83) that Endothyra may essentially have a porous test, and that 

 his specimens may have been modified by infiltration ; but the 

 absence of the true " arenaceous " condition in the Russian drawings 

 is remarkable. 



Von MoUer makes more of the real Nummuline character of 

 Nummulina antiquior than Brady seems to allow (Monogr. p. 148). 

 The Fusulince are conveniently made into several species. One set 

 is divided off (Fiisidinella) as having an Imperforate instead of Pe7'- 

 forate shell. " Bradyina " is a " porous " form coUated with Lituola 

 Benneana as a synonym ; but we have not seen it in the British 

 collections, and in appearance and structure it differs from the 

 Lituola quoted. " Cribrospira " would be a Lituola were its shell- 

 structure sandy, instead of being porous like an immature Val- 

 vulina. 



Among the non-spiral Foraminifera of the Russian Carboniferous 

 series, Von Moller makes his genus " Cribrostomum " the most com- 

 prehensive, with eight species, diflPerentiated by the angle at which 

 the chambers are superimposed, as far as it can be calculated by 

 the production of the probable planes beyond the side walls, thus 

 giving the readings for the " species " in degrees. Taking other 

 characters, however, into consideration, Brady had already treated 

 the same or similar forms as Textularians, referring them to Clima- 

 cammina, Bigenerina patida, and true Textidarice. Indeed, as with 

 other groups of Textularioe having their own peciiliar facies, there 



